obama in mr. romney's mock sessions though tried to lower expectations playing up the president's experience. >> he's been through a lot of those one-on-one debates with a republican. mitt has not, and you think about it, he hasn't had a real debate in ten years because these republican debates tend to be more like candidate forums. >> reporter: tuesday the poet candidates both made whirlwind visits to new york city. president obama addressed the u.n. general assembly, appearing to draw a real line in the sand on iran's efforts to build nuclear weapons. >> make no mistake. a nuclear-armed iran is not a challenge that can be contained >> reporter: strong words didn't satisfy romney. >> we can look at the record of the last four years. is iran closer to a nuclear weapon or not, and we know the answer. it's closer to a nuclear weapon. >> reporter: and both candidates tried to one-up each other in praising bill clinton at the former president's annual conference on global giving. romney joked about th